This invention relates to a device for establishing an accurate bite between the upper and lower teeth after a "root form" implant has been surgically installed in the upper or lower jaw. A conventional technique for positioning implants comprises a step of securing a fixture, which can be threaded or non-threaded, into the jaw bone and leaving it there for a discreet period of time to allow a healing process to take effect, so that the bone becomes biologically attached to the fixture.
The fixture usually comprises a hollow cylinder, the outer and inner curved surfaces of which are provided with threads. It is strategically positioned in such a way that the upper end surface is located at the same level as the surface of the jawbone. During a second step, the healed membrane is cut to expose the upper end surface of the fixture, and a spacer is screwed into the center aperture of the implanted fixture. This fixture will serve as an ultimate attachment of a prosthetic tooth to the anchor.
In order to fabricate a prosthesis over the implants a master model of the patients mouth must be made. One method is to make a replica of each implant an its relationship to any remaining teeth in master model. The other method is to attache a restorative abutment to each implant and make a replica of the relationship of these abutments in a master model.
To make a master model an impression post must be secured to each implant (If the abutments are in place an impression post is secured to each abutment). A standard dental impression is taken with an impression tray and a material such as rubber. When this impression is removed from the mouth, the impression posts are retained in the impression. A replica of the implant or abutment (lab analog) is attached to each impression post that has been retained in the impression. Dental stone is now poured into the impression to make a master model.
At this stage relating this master model accurately to a model of the opposite jaw in the laboratory is difficult without many teeth present in the area of the implants. This usually requires the patient to return to the office for one or more appointments before the prosthesis can be completed. If the initial impression is not accurate, the support structure is cut and reassembled. In some cases, the impression of the patients mouth has to be taken again in an attempt to replicate the relationship of the implants.
The present invention contemplates provision of an implant registration system which can be used to check the accuracy of duplication of the relationship of the implants to each other and the remaining teeth.